   var endTime = new Date("2019/6/10 17:30:00"); 
   var strTime = ""
   setInterval(clock,1000); 
   function clock(){
    var nowTime = new Date(); 
    var second = parseInt((endTime.getTime() - nowTime.getTime()) / 1000);
    
    var d = parseInt(second / 3600 / 24); //天数
   
    var h = parseInt(second / 3600 % 24) // 小时
  
    var m = parseInt((second-h*3600-d*24*3600) / 60 );
    
    var s = parseInt(second-h*3600-d*24*3600-m*60); // 当前的秒
   
    d<10 ? d="0"+d : d;
    h<10 ? h="0"+h : h;
    m<10 ? m="0"+m : m;
    s<10 ? s="0"+s : s;
    
    strTime = "距离抢购开始还有: "+d+"天 "+h+"小时 "+m+"分钟 "+s+"秒"
    $("#dao").html("距离抢购开始还有: "+d+"天 "+h+"小时 "+m+"分钟 "+s+"秒") ;
 
   }